Multiple power flow solutions of small integrated AC/DC power systems

To study the steady state behavior of small integrated AC/DC power systems, a new realization of AC equivalent approach to AC/DC power flow is proposed in this paper. Depending on control modes, the converter AC terminal buses are modeled as constant voltage bus (slack bus) and nonlinear load bus (PI bus). As a result the whole system and corresponding Jacobian matrix become area-decoupled. In this paper we study two control modes through analysis of multiple load flow solutions thus providing a quantitative and qualitative assessment of feasible and controllable system operating points.